Inferring ground-level nitrogen dioxide concentrations at fine spatial resolution applied to the TROPOMI satellite instrument

Satellite-based estimates of ground-level nitrogen dioxide (NO _2 ) concentrations are useful for understanding links between air quality and health. A longstanding question has been why prior satellite-derived surface NO _2 concentrations are biased low with respect to ground-based measurements. In...

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Main Authors: Matthew J Cooper, Randall V Martin, Chris A McLinden, Jeffrey R Brook
Format: Article
Language:English
Published: IOP Publishing 2020-01-01
Series:Environmental Research Letters
Subjects:
Online Access:https://doi.org/10.1088/1748-9326/aba3a5
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author Matthew J Cooper
Randall V Martin
Chris A McLinden
Jeffrey R Brook
author_facet Matthew J Cooper
Randall V Martin
Chris A McLinden
Jeffrey R Brook
author_sort Matthew J Cooper
collection DOAJ
description Satellite-based estimates of ground-level nitrogen dioxide (NO _2 ) concentrations are useful for understanding links between air quality and health. A longstanding question has been why prior satellite-derived surface NO _2 concentrations are biased low with respect to ground-based measurements. In this work we demonstrate that these biases are due to both the coarse resolution of previous satellite NO _2 products and inaccuracies in vertical mixing assumptions used to convert satellite-observed tropospheric columns to surface concentrations. We develop an algorithm that now allows for different mixing assumptions to be used based on observed NO _2 conditions. We then apply this algorithm to observations from the TROPOMI satellite instrument, which has been providing NO _2 column observations at an unprecedented spatial resolution for over a year. This new product achieves estimates of ground-level NO _2 with greater accuracy and higher resolution compared to previous satellite-based estimates from OMI. These comparisons also show that TROPOMI-inferred surface NO _2 concentrations from our updated algorithm have higher correlation and lower bias than those found using TROPOMI and the prior algorithm. TROPOMI-inferred estimates of the population exposed to NO _2 conditions exceeding health standards are at least three times higher than for OMI-inferred estimates. These developments provide an exciting opportunity for air quality monitoring.
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spelling doaj.art-0a13ad0c3e444d2c94368397e0319c092023-08-09T14:53:11ZengIOP PublishingEnvironmental Research Letters1748-93262020-01-01151010401310.1088/1748-9326/aba3a5Inferring ground-level nitrogen dioxide concentrations at fine spatial resolution applied to the TROPOMI satellite instrumentMatthew J Cooper0https://orcid.org/0000-0002-4145-3458Randall V Martin1https://orcid.org/0000-0003-2632-8402Chris A McLinden2https://orcid.org/0000-0001-5054-1380Jeffrey R Brook3Department of Physics and Atmospheric Science, Dalhousie University , Halifax, Nova Scotia, Canada; Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis , St. Louis, MO, United States of America; Author to whom any correspondence should be addressed.Department of Physics and Atmospheric Science, Dalhousie University , Halifax, Nova Scotia, Canada; Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis , St. Louis, MO, United States of America; Harvard-Smithsonian Center for Astrophysics , Cambridge, MA, United States of AmericaEnvironment and Climate Change Canada , Toronto, Ontario, CanadaDalla Lana School of Public Health, University of Toronto , Toronto, Ontario, CanadaSatellite-based estimates of ground-level nitrogen dioxide (NO _2 ) concentrations are useful for understanding links between air quality and health. A longstanding question has been why prior satellite-derived surface NO _2 concentrations are biased low with respect to ground-based measurements. In this work we demonstrate that these biases are due to both the coarse resolution of previous satellite NO _2 products and inaccuracies in vertical mixing assumptions used to convert satellite-observed tropospheric columns to surface concentrations. We develop an algorithm that now allows for different mixing assumptions to be used based on observed NO _2 conditions. We then apply this algorithm to observations from the TROPOMI satellite instrument, which has been providing NO _2 column observations at an unprecedented spatial resolution for over a year. This new product achieves estimates of ground-level NO _2 with greater accuracy and higher resolution compared to previous satellite-based estimates from OMI. These comparisons also show that TROPOMI-inferred surface NO _2 concentrations from our updated algorithm have higher correlation and lower bias than those found using TROPOMI and the prior algorithm. TROPOMI-inferred estimates of the population exposed to NO _2 conditions exceeding health standards are at least three times higher than for OMI-inferred estimates. These developments provide an exciting opportunity for air quality monitoring.https://doi.org/10.1088/1748-9326/aba3a5air qualityNO2TROPOMIremote sensing
spellingShingle Matthew J Cooper
Randall V Martin
Chris A McLinden
Jeffrey R Brook
Inferring ground-level nitrogen dioxide concentrations at fine spatial resolution applied to the TROPOMI satellite instrument
Environmental Research Letters
air quality
NO2
TROPOMI
remote sensing
title Inferring ground-level nitrogen dioxide concentrations at fine spatial resolution applied to the TROPOMI satellite instrument
title_full Inferring ground-level nitrogen dioxide concentrations at fine spatial resolution applied to the TROPOMI satellite instrument
title_fullStr Inferring ground-level nitrogen dioxide concentrations at fine spatial resolution applied to the TROPOMI satellite instrument
title_full_unstemmed Inferring ground-level nitrogen dioxide concentrations at fine spatial resolution applied to the TROPOMI satellite instrument
title_short Inferring ground-level nitrogen dioxide concentrations at fine spatial resolution applied to the TROPOMI satellite instrument
title_sort inferring ground level nitrogen dioxide concentrations at fine spatial resolution applied to the tropomi satellite instrument
topic air quality
NO2
TROPOMI
remote sensing
url https://doi.org/10.1088/1748-9326/aba3a5
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